The most amazing thing about life, is that, many people don't still know how the mind is functional to their actions in life. They see mind as something always and forever abstract, there by, its unenable to transform into reality.
The day you start making use of your mind as a tool to solve problems, life would be much easier.
Mind is the ability to think and retain what is been thought, therefore what I think is what happens, do you belive that?. Well, I have good news for you, which is"whatever you believe works for you". What if you believe that having a positive mind set and thinking would be beneficial for you? It's doesn't extract anything from you when you feed your mind with positivism, it only add values to you but if you feed your mind with negativity, then be sure of getting negative results all the time. Conciously recognizing the power of the mind and believing in it, is the greatest achievement one can boast about.
My Experience
I could remember an incident that took place when I was in my 200 level. There were rumors going on at school, that I was amongst the 89 students out of 110 that failed a very difficult course in my department which means a carry over. I told them that it can't be, that I prepared so well for that course. I believed I was going to come out with a good grade even when I saw every reason not to believe positively due to the rumours in school. Eventually, the results came out and I had a "B" and they were all surprised. So it's best for you to be a positive thinker and expect the best from yourself.
Therefore, the food for our minds are virtue, positivism, excellence, and things that doesn't go contratry to your utmost desires. Let's us not dwell on negativity but look forward to seeing the best out of every situation in our lives.
Also, seeing the best from every bleak situation would envelope you to an atmosphere of gratitudes because the little before you is enough to give thanks. Positive mind produces a thanksgiving heart which also produces full time happiness. Stay on the train.